Ytterbium-aromatic imine dianion complexes, easily prepared from ytterbium metal and aromatic imines, can act as effective catalysts for the isomerization of terminal alkynes to afford internal alkynes in good to high yields.
作者:Rama M Hindupur、Bijoy Panicker、Muralikrishna Valluri、Mitchell A Avery
DOI:10.1016/s0040-4039(01)01585-4
日期:2001.10
A convergent totalsynthesis of epothilone A (1) is described. The key steps are diastereoselective aldol condensation of aldehyde 3 to form the C6C7 bond; macrolactonization and Wadsworth–Emmons reaction of methyl ketone with phosphonate reagent 5.
Electronic Character of α,3‐Dehydrotoluene Intermediates Generated from Isolable Allenyne‐Containing Substrates
作者:Qian Xu、Thomas R. Hoye
DOI:10.1002/anie.202207510
日期:2022.10.4
α,3-Dehydroluenes (DHT), a relatively rare class of reactive intermediate(s), can be formed by warming isolableallenynes bearing a remote alkyne or nitrile. The product distributions produced in solvents of different polarity give insight to the electronic nature/structure of the DHTs (zwitterion vs. diradical vs. cyclic allene).
Synergistic Porosity and Charge Effects in a Supramolecular Porphyrin Cage Promote Efficient Photocatalytic CO
<sub>2</sub>
Reduction**
作者:Lun An、Patricia De La Torre、Peter T. Smith、Mina R. Narouz、Christopher J. Chang
DOI:10.1002/anie.202209396
日期:2023.1.26
We present a supramolecular strategy to enhance photochemical reduction of CO2 to CO leveraging synergy between multiple second-sphere interactions. Post-synthetic click chemistry enables modular synthesis of porous porphyrin organic cages bearing 24 cationic groups. The coordinated use of both porosity and charge to augment CO2 reduction activity beyond additive effects results in fast and selective
我们提出了一种超分子策略,利用多个第二球相互作用之间的协同作用,增强 CO 2光化学还原为 CO。合成后点击化学能够模块化合成带有 24 个阳离子基团的多孔卟啉有机笼。协调使用孔隙率和电荷来增强CO 2还原活性,使其超出加和效应,从而在低CO 2浓度下实现快速且选择性的催化。
Optimization study of Sonogashira cross-coupling reaction on high-loading macrobeads using a silyl linker
作者:Yun Liao、Reza Fathi、Mike Reitman、Yan Zhang、Zhen Yang
DOI:10.1016/s0040-4039(01)00052-1
日期:2001.3
Two types of Sonogashira reactions were systematically evaluated on silyl linker based high-loading polystyrene macrobeads, this study paves the way fur their future application in the combinatorial syntheses of some natural product-like molecules. (C) 2001 Elsevier Science Ltd. All rights reserved.